I uses a trick when traveling - when I am in a hotel and go out I always turn on the TV. This way no one is sure that I am not in the room. I also leave on a light.
You could do the same at home. Turn on the TV and put a timer on some of your lights. Set the timers to go on and off at different times. Some timers can handle multiple programs, so you could turn on and off a light in the same room a couple or more times. You can also get a computer program to do this.
Record a barking dog and have it playing - just make sure it is not the same small loop.
Cardboard cutouts of humans to make a shadow in your window - works if you have a rocking chair. (but hard to do)
If this is a gang of some sort and not neighborhood kids - they will soon leave when it gets too hot for them.
If you have a small sherrif office - can they place a dummy car in the area?
Finally - living in fear is not good - stuff happens and all you can do is protect you and your family. It sounds as if you are in the country - can you do a little target shooting? Do that every day - maybe someone watching will get the idea that your place is well protected.
Check out these sites for good ideas: (you got me thinking about installing cameras again)
http://www.homesecurityinformation.com/ideas/http://softwarebizsummit.com/http://www.homesecurityinformation.com/